Crimped tube coupling and a crimping apparatus for making a crimped tube coupling

ABSTRACT

A tube coupling ( 10 ) has a tubular fitting ( 14 ) with a nipple ( 18 ) with at least one exterior annular groove ( 20 ). A deformable tube ( 12 ) has one end to fit over the nipple and has a crimp section ( 28 ) deformed into the groove with longitudinally extending ribs ( 30 ) circumferentially spared about the tube.

TECHNICAL FIELD

The field of this invention relates to a crimping die machine and a crimp construction.

BACKGROUND OF THE DISCLOSURE

Crimping die tools have long been used to produce a crimp that connects a fitting onto a hose. The crimp die tools are often complicated pieces of machinery with many moving parts and often several crimping fingers having different lengths and different shaped cam ends to complement the die tool drive mechanism. Because of the individuality of each finger, inventory for spare parts becomes burdensome.

It is also known that rigid tubing used to transfer gases during the actuation of side airbags in automotive vehicles is commonly fastened to the gas supply canister via a threaded fitting on the canister connected to a nut on the tubing.

What is needed is lighter weight connection between the canister and the tubing that is adapted for a single high pressure use. What is needed is a tube that is crimped onto a fitting for the canister with a structurally secure and tight crimped connection that only requires the tube and fitting to achieve the crimp and eliminate the need for fastener items, for example, ferrules, clamps, threaded fasteners, gaskets and adhesives.

What is also needed a crimping apparatus that has interchangeable crimping fingers which are driven to simultaneously achieve the closed position.

SUMMARY OF THE DISCLOSURE

In accordance with one aspect of the invention, a tube coupling has a tubular fitting with a central passage and an annular wall with at least one exterior annular groove. Preferably, the fitting has two exterior annular grooves axially spaced from each other with an exterior raised ring section interposed therebetween. A tube being made of a normally rigid but deformable under heavy loads material, for example steel, has one end with an internal diameter sized to fit over the fitting. If needed or preferred, the tube end can be swaged up or down to accommodate the fitting. The tube has a crimp section deformed to be crimped into the annular groove to also have two exterior annular grooves or crimped. The tube also has a plurality of longitudinally extending ribs spanning the crimp section circumferentially spaced about the tube. The ribs span each of the crimped sections. The ribs are formed by deformation of the tube wall by folding of the wall onto itself. The thickness of each rib is slightly less than twice the thickness of the tube material from its inner and outer diameter. Preferably in order to make an effective crimp, the amount of tube material extruded from the grooves corresponds to the amount of material used to form the ribs.

In one embodiment, the exterior raised ring section is tapered toward its outer diameter with an outer diameter wall and opposing canted walls. The crimp sections have opposing walls abutting the opposing canted walls.

In accordance with another aspect of the invention, a crimping machine for crimping a tube over a grooved fitting has first and second driver bases with first and second cages respectively mounted thereon. The first driver base and first cage are movable with respect to the second driver base and second cage between a closed position and an open position. At least one crimp die finger having a jaw tooth is mounted on each cage for movement between an open and closed position. Each die finger has distal wall sections that abut an adjacent finger when in the closed position. The jaw tooth ends short of the distal wall sections to form a notch such that when adjacent fingers are in a closed position, the notches provide a gap between the fingers in which the tube can be deformed.

In accordance with another aspect of the invention, a crimping machine has a plurality of crimp die fingers mounted in each cage. One of the crimp die fingers in each cage is aligned along the axis of motion of the cages and moves with respect to its cage along the axis of motion. The remaining crimp die fingers have their longitudinal axis set at an angle from the axis of motion of the cage and move along their longitudinal axis i.e. canted relative to the axis of motion of the cage.

The driver base is preferably movably connected to the respective mounted cage. Each driver base has a drive surface perpendicular to the axis of motion of the cage section for engaging the one aligned crimp die finger. The driver base also has canted drive surfaces angled with respect to the axis of motion of the cage section for abutting the remaining crimp die fingers. The crimp die fingers are movable in each cage as each cage moves from an open position to a closed position. The driver base is movable from its open position to its closed position to move all the crimp die fingers in the cages to achieve a closed crimping position simultaneously.

In one embodiment, the respective driver base is spring loaded away from its respective cage. The crimp die fingers are also spring loaded in their cages toward the open position.

In accordance with another aspect of the invention, a crimping machine for crimping a tube over a grooved fitting has first and second driver bases with first and second cages respectively mounted thereon. The first driver base and cage are movable with respect to the second driver base and cage between a closed position and an open position. Each cage has a plurality of crimp die fingers arranged circumferentially about a central axis between the two cages when in a closed position. Each crimp die finger in each cage has the same length and having a flat proximate drive end and a distal jaw end. The crimp die fingers are set at varying angles from the axis of motion of the cage. Each driver base is movably connected to its respective mounted cage. Each driver base has a plurality of drive surfaces fixed with respect to each other and flushly abut the flat proximate drive end of a respective crimp die finger. Some of these drive surfaces are angled with respect to the axis of motion of the cages for flushly abutting respective crimp die fingers. The crimp die fingers are movable in each cage as each cage moves from an open position to a closed position. The driver base is movable from its open position to its closed position to move all the crimp die fingers in the cages at rates to achieve a closed crimping position simultaneously.

In accordance with another aspect of the invention, a crimp die for a crimp die machine has its jaw tooth ending short of its distal wall section such that two crimp dies are in the closed position and the distal wall sections are in abutment, a gap is formed between the jaw teeth of adjacent crimp dies.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference now is made to the accompanying drawings in which:

FIG. 1 is a perspective view of a fitting with one tube crimped thereon in accordance with one embodiment of the invention;

FIG. 2 is a perspective view of the fitting member shown in FIG. 1;

FIG. 3 is a perspective view of a fitting and tube assembly with a modified crimp connection;

FIG. 4 is a fragmentary cross sectional taken along line 44 shown in FIG. 3;

FIG. 5 is cross sectional view taken along line 5-5 shown in FIG. 1;

FIG. 6 is a side elevational and partially schematic view of a crimp die machine for producing the crimp shown in FIG. 1 with the bottom cage shown in an open position and the top cage shown in the closed crimping position;

FIG. 7 is a view similar to FIG. 6 showing the two cages pressed together and crimp die machine in the closed crimping position;

FIG. 8 is an enlarged fragmentary side elevational view of a crimping finger shown in FIG. 6;

FIG. 9 is a cross sectional view taken along line 9-9 shown in FIG. 8;

FIG. 10 is a side elevational and partially schematic view of an alternate crimp die machine that produces the crimp connection shown in FIG. 3 with the bottom cage shown in the open position and the top cage shown in the closed crimping position;

FIG. 11 is an enlarged fragmentary view of the jaw ends of the crimping fingers shown in FIG. 10 in the closed and crimping position; and

FIG. 12 is a cross sectional view taken along line 12-12 shown in FIG. 11.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to FIGS. 1 and 2, a metal tube 12 is crimped onto a fitting 14 to form a crimp connection 10. The tube is made from a deformable metal, for example steel, and has a swaged enlarged end 16 sized is to fit over the fitting nipple 18. The fitting nipple 18 has two grooves 20 therein with an annular raised ring section 22 therebetween. Each side wall 24, 26 of the ring section 22, and outer walls 27, 29 of the grooves may have a cant of approximately 35°. It is foreseen that for most application the cant of side walls 24, 26, 27, and 29 may range from 30° to 40°. In one embodiment, walls 24 and 27 may have a different cant than walls 26 and 29. The fitting 14 may have two opposing nipples 18 and a body section 34 with two flange sections 38 that is connectable to a side airbag canister (not shown). Each nipple 18 has a conduit 40 which passes therethrough and fluidly communicates with a passage 42 in the body as shown in FIG. 4.

The enlarged swaged end 16 of tube 12 has two crimp sections 28 of reduced diameter that protrude into the grooves 20 to snugly abut the outer surface of the nipple 18. A plurality of longitudinal ribs 30 longitudinally span across each crimp section 28. FIG. 1 discloses an embodiment with six ribs circumferentially spaced about each crimp section 28.

As shown in FIG. 3, an alternative crimp connection 10 is shown with the major structural difference being that this embodiment has only two ribs 30 in each groove 20 circumferentially spaced 180° apart.

Each rib 30 is formed by the wall of the tube doubled over as shown in FIG. 4 such that a inner surface 44 of the tube abuts itself. The thickness of the rib 30 is slightly less than twice the thickness of the tube material in order to assure that the deformed metal about the rib provides for a tight abutment of the inner surface 44 with the nipple 18.

An apparatus 50 that tightly crimps the tube 12 onto the fitting 14 is shown in FIG. 6. The apparatus 50 has opposing cages 52 connected to the driving base 54. Each cage 52 is provided with recesses to house three identical crimping fingers 56, 58, 60 circumferentially positioned about a central longitudinal axis 62. Crimping finger 56 is aligned along the axis of motion 69 of the driving plate 54 while fingers 58 and 60 are at opposite canted 60° angles from the axis of motion 69 of the cage. Each finger 56, 58 and 60 are identically constructed with equal length and a flat proximate drive end 64 and distal jaw ends 66. Drive end 64 of finger 56 directly and flushly abuts the drive base 54 often referred to as a base plate. The proximate drive ends 64 of fingers 58 and 60 flushly abut a canted surface 66 of a wedge 68 which is in turn securely connected to the drive base 54 and moves therewith. The direction of motion of each finger 58, 60 in each cage is set to be normal to the canted surface 66 and set at an angle with respect to the axis portion of 69 of the cage 52 between its closed and open position.

Each finger 56, 58 and 60 has a lug 70 which intrudes into a recess pocket 72 in cage 52 and abuts a compression spring 74 to bias each finger radially outwardly as shown in the bottom cage 52 shown in FIG. 6.

The drive base 54 is spring loaded via a compression spring 76 away from cage 52 when the plate 54 and connected wedges 68 are biased away, the springs 72 move the fingers 56, 58 and 60 radially outward as shown at the bottom cage 52 in FIG. 6.

The drive bases 54 can be pressed together via a machine press (not shown) to move the cages 52 together until they abut each other. After the cages abut each other, further pressing of the plates 54 will overcome the compression springs 76 and move the plates 54 toward the cages 52 to drive the fingers 56 radially inward. The wedges 68 simultaneously move longitudinally with respect to the cage 52 and has its surface 66 both slide with respect to drive ends 64 and drive the canted fingers 58 and 60 radially inward. All the fingers move inwardly in a fashion to achieve a closed position simultaneously as shown in FIG. 7. When the fitting and tube is in position in the cages, the jaws 80 of fingers 56, 58, and 60 will deform the tube 12 to form the crimp sections 28 in the grooves 20 with the ribs 30.

As shown in FIG. 8, the jaws 80 of each finger 56, 58, 60 has a jaw tooth 82 and sidewalls 84. The sidewalls are constructed to abut similar sidewalls 84 of an adjacent finger when in the closed position. Jaw teeth 82 stop short of sidewall 84 to form a notch 86. When two adjacent jaws 82 are in the closed position, two notches 86 are adjacent each other to form a gap 88 in which the metal of tube 12 is deformed therein and forms the rib 30. The gap as shown in FIG. 7 is slightly less than the thickness of two wall thicknesses of the tube 12.

While FIGS. 6 and 7 disclose symmetrical and identical fingers with identical jaws 84 and jaw teeth 82 each spanning an equal arcuate portion i.e. approximately 60°, it is also foreseen that due to clearance problems where ribs 30 need to be spaced irregularly circumferentially about the tube, jaws ends may each have its jaw teeth span different angles such that the ribs can be shifted to a desired circumferential position.

While fingers 58 and 60 have the same length as finger 56, they are positioned at different angles and thus are set different initial distance fingers when in their open position from the center axis 62 as shown in FIG. 6 so that when wedge 68 drives the jaws 58 and 60, there is less radial movement of the fingers 58 and 60 compared to fingers 56. However all the jaws 80 achieve the closed position and shown in FIG. 7 simultaneously. The distance needed for driving the canted fingers 58 and 60 relative to shift rate position to finger 56 is determined by the angle of the canted surface 66 of the wedge 68 by using the cosine relative to the plane of the drive base 54; i.e. the distance traveled by finger 56 can be multiplied by the cosine 60°. If the wedge surface 64 is set at other angles, the cosine of the other set angle is used to determine fingers 58 and 60 distance from the closed position. This calculated distance assumes that the direction of travel of the finger 58, 60 in cage 52, i.e. its radial travel is normal to the wedge surface 64. If the direction of travel is not normal, the distance is increased depending on how far off normal the finger's direction of travel in the cage is from the wedge surface 54. It can be foreseen that different number of fingers can be set at different angles with all the fingers achieving the closed position simultaneously.

Referring now to FIGS. 10, 11 and 12, a modified crimping apparatus 50 is shown. Corresponding parts will have the same designated numerals for ease of comparison. In this apparatus, the same drive bases 54 can be used. Each cage 52 is constructed to house a single finger 56 that is axially aligned with the axis of motion 69 of the drive base 54. Each finger 56 has its proximate drive end 64 abut the drive base 54. Jaw 80 is constructed similarly as the previously described jaw with the major exception being that the span of the jaw 80 is approximately 180° minus room for the notch 86. The distal ends 90 of each finger 56 abut each other in the closed position as shown in FIG. 11. The two notches 86 form gap 88 in which oppositely positioned ribs 30 are formed in the crimp connection.

One advantage of having the ribs 30 extend longitudinally along the crimp 28 is increased structural strength against longitudinally directed pull forces that may want to separate the tube 12 from the fitting 14. Two crimp sections 28 each having ribs 30 reinforcing the crimp connection 10 provides for a structurally sound and sealed connection.

The crimping apparatus can be found to be advantageous. The machine uses identical fingers such that the single finger may be replaced from a common stock. Each finger's travel distance to and from the closed position is simply calculated and constructed to achieve a simultaneous closing with the other fingers.

While the application of this crimp connection is described to be used for side air bag canister connections, it is easily foreseen that other applications may be suitable for this crimp connection.

Variations and modifications are possible without departing from the scope and spirit of the present invention as defined by the appended claims. 

1. A tube coupling comprising: a tubular fitting having a central passage, an annular wall with at least one exterior annular groove; a tube being made of a deformable material having one end sized to fit over said fitting; said tube having a crimp section deformed to be crimped into said annular groove; said tube having a plurality of longitudinally extending ribs spanning said crimp section circumferentially spaced about said tube.
 2. A tube coupling as defined in claim 1 further comprising: said fitting having two exterior annular grooves axially spaced from each other with an exterior raised ring section interposed therebetween.
 3. A tube coupling as defined in claim 2 further comprising: said exterior raised ring section tapered toward its outer diameter with an outer diameter wall and opposing canted walls; and said crimp sections having opposing walls abutting said opposing canted walls.
 4. A tube coupling as defined in claim 3 further comprising: said ribs spanning each of said crimped sections; and said ribs formed by deformation of said tube wall by folding said wall onto itself and said thickness of said ribs being slightly less than twice the thickness of said tube material from its inner and outer diameter.
 5. A crimping machine for crimping a tube over a grooved fitting said machine comprising: a first driver base and a first cage mounted thereon; a second driver base and a second cage mounted thereon; said first driver base and first cage movable with respect to the second driver base and second cage between a closed position and an open position; and at least one crimp die finger having a jaw tooth mounted on each cage for movement between an open and closed position; said at least one die finger having distal wall sections that abut an adjacent finger when in the closed position; said jaw tooth ending short of the distal wall sections to form a notch in said finger such that when adjacent fingers are in a closed position, said notches provide a gap between said fingers in which said tube can be deformed.
 6. A crimping machine as defined in claim 5 further comprising: each cage having a plurality of crimp die fingers; one of said crimp die fingers in each cage being aligned along the axis of motion of said cage; the remaining crimp die fingers set at an angle from the axis of motion of said cage; said driver base movably connected to said respective mounted cage; each driver base having a drive surface perpendicular to the axis of motion of said cage section for engaging said one of said crimp die fingers; opposing canted drive surfaces angled with respect to the axis of motion of said cage for abutting the remaining crimp die fingers; said crimp die fingers being movable in each cage as said cage moves from an open position to a closed position; and said driver base movable from its open position to its closed position to move all the crimp die fingers in said cages to achieve a closed crimping position simultaneously.
 7. A crimp machine as defined in claim 6 further comprising: said respective driver base being spring loaded away from its respective cage; and said crimp die fingers being spring loaded in their cages toward the open position.
 8. A crimp die for a crimp die machine; said crimp die having its jaw tooth ending short of its distal wall section such that two crimp dies are in the closed position and the distal wall sections are in abutment, a gap is formed between the jaw teeth of adjacent crimp dies.
 9. A crimping machine for crimping a tube over a grooved fitting said machine comprising: a first driver base and a first cage mounted thereon; a second driver base and a second cage mounted thereon; said first driver base and cage movable with respect to the second driver base and cage between a closed position and an open position; each cage having a plurality of crimp die fingers; one of said crimp die fingers in each cage being aligned along the axis of motion of said cage; and remaining crimp die fingers set canted from the axis of motion of said cage. said driver base movably connected to said respective mounted cage; each driver base having a drive surface perpendicular to the axis of motion of said cage section for engaging said one of said crimp die fingers; opposing canted drive surfaces angled with respect to the axis of motion of said cage section for abutting the remaining crimp die fingers; said crimp die fingers being movable in each cage as each cage moves from an open position to a closed position; and said driver base movable from its open position to its closed position to move all the crimp die fingers in said cages to achieve a closed crimping position simultaneously.
 10. A crimp machine as defined in claim 9 further comprising: said respective driver base being spring loaded away from its respective cage; and said crimp die fingers being spring biased in its cage toward the open position.
 11. A crimping machine for crimping a tube over a grooved fitting said machine comprising: a first driver base and a first cage mounted thereon; a second driver base and a second cage mounted thereon; said first driver base and cage movable with respect to the second driver base and cage between a closed position and an open position; each cage having a plurality of crimp die fingers arranged circumferentially about a central axis between the two cages when in a closed position; each crimp die finger in each cage having the same length and having a flat proximate drive end and a distal jaw end; said crimp die fingers set at varying angles from the axis of motion of said cage; said driver base movably connected to said respective mounted cage; each driver base having a plurality of drive surfaces fixed with respect to each other and to flushly abut the flat proximate drive end of said crimp die fingers; some of said drive surfaces being angled with respect to the axis of motion of said cage section for flushly abutting respective crimp die fingers; said crimp die fingers being movable in each cage as each cage moves from an open position to a closed position; and said driver base movable from its open position to its closed position to move all the crimp die fingers in said cages at rates to achieve a closed crimping position simultaneously.
 12. A crimp machine as defined in claim 11 further comprising: said respective driver base being spring loaded away from its respective cage; and said crimp die fingers being spring loaded in their cages toward the open position.
 13. A crimping machine as defined in claim 12 further comprising: each cage having a plurality of crimp die fingers; one of said crimp die fingers in each cage being aligned along the axis of motion of said cage.
 14. A crimping machine as defined in claim 11 further comprising: each cage having a plurality of crimp die fingers; one of said crimp die fingers in each cage being aligned along the axis of motion of said cage. 